"The key with this case, assuming you don't find Robyn Gardner, is that you're going to have to put together a very strong circumstantial case-- that it was premeditated, that he used a ruse to get her there, for example," he said. "When you add this to the apparent behavior of treating women in a certain fashion, stalking or potentially violent, it certainly adds to the case. Added to all the other things, it's substantial."
New details also emerged about the hours leading up to Gardner's disappearance, including evidence of blood not far from the beach where Gardner was supposedly snorkeling when she was swept out to sea.
A police source in Aruba told ABC News that restaurant staff at the Rum Reef Bar & Grill noticed that Gardner seemed woozy while she and Giordano ate on the afternoon of her disappearance. Giordano later told police they'd been drinking vodka at the Marriot before dining and that she'd taken sleeping pills earlier in the day.
Authorities said that they found blood on a rock behind the dive shop at Rum Reef, which is the last place the two were seen together. Surveillance video from the restaurant shows Giordano in his rental car parked in the back of the bar and restaurant twice, which he told police was so that he could park in the shade, according to the police source. No one else is visible through the car's tinted windows.
Investigators have also said that they had trouble identifying Giordano in surveillance video because he frequently changed his toupees.
At 6:20 p.m. on the day of her disappearance, police were called, and 20 minutes later began to search the area. Then, Giordano left the search to return to his hotel and take a nap, according to police.
After three days, Giordano returned his rental car and headed to the airport, where a ticket agent asked him about his travel companion and he responded, "She's taking another flight," police said.
When he was arrested by Aruban police, they said Giordano was drenched in sweat.